monotonic_time
for timing, since it isn't
affected by OS clock changes.
System.monotonic_time/1
Returns the current monotonic time in the given time unit. The time is monotonically increasing and starts in an unspecified point in time.
= System.monotonic_time(:microseconds)
start_time
# do something
= System.monotonic_time(:microseconds)
end_time
= end_time - start_time duration_in_microseconds